Los Angeles, California (CNN) -- Brooke Mueller checked into a treatment facility for help with stress management to prevent a "return to old problems" -- but don't call it rehab, her representative said Wednesday.

Mueller and her husband, actor Charlie Sheen, are living separately, but neither has filed for divorce, a source close to the situation told CNN Wednesday.

Mueller was in substance abuse rehab earlier this year "to get her health in order," her lawyer, Yale Galanter, said at the time.

A "red light went on" recently that Mueller recognized has "the potential of challenging sobriety," representative Elliot Mintz said Wednesday.

"We all have different various ways of dealing with stress. Some of us work out, some of us stay in bed, some of us meditate. Some of us, like Brooke, there is the possibility that she will return to old problems, so she decided (to get help)," Mintz said.

The treatment, intended to avoid "things that lead people into troubled waters," could take three weeks or longer, he said.

Mintz would not reveal where Mueller has gone for help, but he did say it was "not in one of those rehab places that you would recognize in a distant land."

Mintz would not comment on reports that Mueller and Sheen have prepared divorce documents, saying his focus is helping her get beyond her stress issues.

The source close to the situation says documents outlined on the celebrity news website TMZ are an "understanding" drawn up some time ago -- setting out the terms and agreements of a divorce should either party seek one.

Sheen, 44, and Mueller, 32, were involved in an alleged domestic dispute in Aspen, Colorado, on Christmas Day that resulted in felony charges against Sheen.

The couple married in 2008. Their twin sons, Max and Bob, had their first birthday in March.